Traffic signaling system



1942- K. MULLERHEIM TRAFFIC SIGNALING SYSTEM Filed Aug. 31, 1940 5?? 8;. n 3.. SE 2; .20 61 w u k on ma 295.5 E; o 86 Imam-00mm RAILWAY [O INVENTO R KURT MULLERHEIM ATTOR NEYS' Patented Jan. 27, 1942 UNITED STATES PATENT OFFICE TRAFFIC SIGNAIJNG SYSTEM Kurt Mullerheim, Chicago, Ill., assignor to Associated ElectricLaboratories, Inc., Chicago, 111., a corporation of Delaware Application August 31, 1940, Scrial'N 0. 355,005

9 Claims.

The present invention relates to signaling systems and more particularly to railway traflic signaling systems. More specifically, the invention relates to improvements in railway traffic signaling systems of the character of that disclosed in U. S. Patent No. 2,037,256, John S. Miller, granted April 14, 1936.

A railway trafiic signaling system conventionally comprises a stretch of railway track along which vehicles are adapted to travel in either direction, a number of way stations associated with the stretch of railway track, a signal line associated with both the Way stations and with one or more dispatcher stations, and apparatus at each way station which is responsive to the passage of a vehicle traveling in a given direction over a fixed point along the stretch of railway track associated with the way station for sending a signal over the signal line indicative of both the given direction of travel of the vehicle and the fixed point or way station.

In a signaling system of this character, it has been proposed that the apparatus at each way station should be so connected and arranged that.

permits of considerable delay in the sending of signals, particularly when the signal line is busy only in connection with the sending of ordinary messages between the various dispatcher stay tions.

Accordingly, it is an object of the present invention to provide a signaling system of the type described, wherein each way station comprises apparatus for testing repeatedly at spaced time intervals the idle or busy conditions of the signal line and for withholding the sending of the signal when the signal line istested busy repeatedly only a predetermined time interval corresponding to a predetermined number of tests. This improved arrangement not only insures that there will be a minimum of interference between various signals sent over the signal line, but it ting limited interference with ordinary messages sent overthe signal line.

Another object of the invention is to providev in a signaling system of the type described, an

improved arrangement for controlling both the conditions under which signals aresent over the signal line'and the repeated sending'of the signals over the signal line.

In general, the objects, as set forth above, are attained in accordance with the presentinvention by providing in a trafiic signaling system of the character described, improved apparatus at each way station, which comprises a sender, means responsive to the passage of a vehicle traveling in either one of the directions over a fixed point along the stretch of railway track associated with the way station for conditioning the sender to be operative to send a signal over the signal line indicative of both the one direction of travel of the vehicle and of the fixed point or way station and for testing repeatedly at spaced time intervals the idle or busy condition of the signal line, means controlled in response to the testing of the signal line as idle for operating the sender, and additional means controlled in response to the testing of the signal line as busy a predetermined number of times for operating the sender, regardless of the busy condition of the signal line. More particularly, the apparatus comprises a sending switch which is operative repeatedly through a cycle at spaced time intervals, a counting switch and a control network. The passage of the train over the fixed point along the stretch of railway track initiates operation "of the sending switch, whereby the idleor busy condition of the signal line is tested repeatedly; and the sending switch is operatively connected to the signal line when the signal line is tested as idle. The counting switch is operated each time the signal line is tested as busy; and when it is operated a predetermined number of times it is effective to cause the sending switch to be operatively connected to the/signal line, regardless of the busy condition thereof, whereupon the counting switch is released. Further, the counting switch is operated in, response to each operation of the sending switch to send the signal over the signal line, and is effective in response to the last-mentioned operation thereof a given number of times to arrest operation of the sending switch.

Further features of the invention pertain to also eXpediteS the send'ingyo'f S s by permit- 65, the particular arrangement of the circuit elemerits, whereby the above-outlined and additional operating features are attained.

The novel features believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawing, in which the single figure is a diagrammatic illustration of a traffic signaling system having embodied therein the features of the present invention.

Referring now more particularly to the drawing, the traffic signaling system there illustrated includes a stretch of railway track Iii along which traffic normally moves either from north to south or from south to north, as indicated by the arrow. Associated with the stretch of railway track II) are a number of way stations, including the way stations indicated at WS30 and WS3I, the way station W830 being associated with the stretch of railway track It] adjacent two track sections IliA and I513 provided therein. The stretch of. railway track IE includes two track rails II and I2 which are divided by suitable insulating joints I3 to form the two track sections WA and I013. The track sections ISA and IGB are provided with individual track circuits, including batteries I5, resistors I5 and track relays R50 and R55, re-

spectively.

The signaling system also includes a number of dispatcher or telegraph stations, including the telegraph stations T820 and TS25, and a telegraph line connecting the various telegraph stations and the various way stations in series circuit relationship. More particularly, the sections of the telegraph line respectively connecting the telegraph station TS20 and the way station W835, the way station W835 and the way station WSSI, and the way station WS3I and the telegraph station TS25, are respectively indicated at 45, M and 42. Each telegraph station comprises apparatus including a telegraph sender of any suitable type, either manual or automatic, and a telegraph recorder of any suitable type. The apparatus provided at the telegraph stations T820 and TS25 respectively comprise the telegraph senders 2I and 21 and the telegraph recorders 22 and 25.

Preferably, the apparatus provided at each way station is substantially identical to that provided at the way station W830 which comprises, in addition to the track relays R58 and R55 respectively associated with the track sections IIlA and IE3 of the stretch of railway track ID, a relay network including a line relay R60, two lockout relays R and R80, a cut-in relay R90 of the differential type, a test relay RIDO, a hold relay RIM of the slow-to-release type, a send relay RIZB of the differential type and a step relay RIM. Also, the apparatus provided at the way station WSSU comprises a counting switch I40 of the minor type, including two wipers I M and I62 provided with individually associated contact banks, a rotay magnet MI43 for driving the wipers noted step by step in the counterclockwise direction away from their normal positions and a release magnet MiM for releasing the wipers noted and for causing them to be returned to their normal positions. Also, associated with the counting switch hill is a set of switch springs S3955 which is actuated in accordance with the movement of the wipers noted away from their normal positions. Further, the apparatus provided at the way station WS3D comprises a sending switch I50 of the rotary type, including four wipers I5I, I52, I53 and I54 provided with individually associated contact banks, and a motor magnet MI 55 for driving the wipers noted step by step in the counterclockwise direction away from their normal positions.

It is noted that each way station has a designation individual thereto, the designation of the way station WS30 being A and B; while each train traversing the stretch of railway track I0 and passing the way station W830 will be traveling either north or south. Accordingly, the sending switch I58 is connected and arranged to send either the codes N, A and B or S, A and B over the associated telegraph line. In order to accomplish this end, the contact banks associated with the wipers noted of the sending switch I50 are wired in accordance with the codes mentioned, standard Morse code being utilized. More particularly, the upper portion of the contact bank associated with the wiper I5I and the lower portion of the contact bank associated with the wiper I52 are respectively wired in accordance with Morse code A and Morse code B; while the lower portions of the contact banks respectively associated with the wipers I53 and I54 are respectively wired in accordance with Morse code S and Morse code KEN",

Referring now to the operation of the signaling system, when the stretch of railway track I!) is clear of trains, the track circuits individual to the track sections IilA and IElB are completed, thereby to energize the windings of-the track relays R50 and R55, respectively, from the batteries I5 by way of the resistors I5. The operated track relay R52! retains interrupted, at the contacts 5|, a circuit traced hereinafter for energizing the upper winding of the lockout relay R30; and the operated track relay R55 retains interrupted, at the contacts 56, a circuit traced hereinafter for energizing the upper winding of the lockout relay R'IO. Also, when the telegraph line extending between the various telegraph stations and the various way stations is idle, a series circuit is normally completed, which extends from the positive terminal of battery by way of the telegraph sender 21 and the telegraph recorder 25 in the telegraph station T825, the section 52 of the telegraph line, the apparatus in the way station WSEH, the section 4| of the telegraph line, the resistor 43 and the contacts 92 and I2I in the apparatus in the way station WS3Q, the section 40 of the telegraph line, and the telegraph recorder 22 and the telegraph sender 2I in the telegraph station TSEI) to the negative terminal of battery.

It will be understood that the dispatcher at the telegraph station TS2II may send a message over the telegraph line by suitably operating the telegraph sender 2 I; that the dispatcher at the telegraph station TS25 may send a message over the telegraph line by suitably operating the telegraph sender 2'I; and that the apparatus in either the way station W S3!) 'or the apparatus in the way station WSSI may send codes automatically over the telegraph line. Also, it is noted that a message or a code sent over the telegraph line is automatically recorded by the telegraph recorders 22 and 26 respectively disposed in the telegraph stations T320 and T625. Further, it is noted that, when a message or a code is being sent over the telegraph line, the telegraph line is rendered busy, for a purpose more I fully explained hereinafter.

When a train traversing the stretch of railway track I I] from north to south enters the track section I 8A, the winding of the track relay R59 is short-circuited, thereby to cause the latter relay to restore. Upon restoring, the track relay R59 completes, at the contacts I, the previously mentioned circuit for energizing the upper winding of the lockout relay R89, this circuit extending from the positive terminal of battery by way of the contacts 5| and II and the upper winding of R80 to the negative terminal of battery.- When thus energized, the lookout relay R89 operates to interrupt, at the contacts 83, a point in the previously mentioned circuit for energizing the upper winding of the lockout relay R; and prepares, at the contacts 84, a circuit traced hereinafter for energizing the lower winding of the send relay RI29 and including the lower portion of the contact bank associated with the wiper I53 of the sending switch I59.

When the train traversing the stretch of railway track I 9 enters the track section I 9B the winding of the track relay R55 is short-circuited, thereby to cause the latter relay to restore. Upon restoring, the track relay R55 completes, at the contacts 56, a holding circuit for energizing the lower winding of the lockout relay R89 and a circuit for energizing the upper winding of the cut-in relay R99. The holding circuit for energizing the lower winding of the lookout relay R89 extends from the positive terminal of battery by 7 way of the contacts 56, 82 and 8I and the lower winding of R89 to the negative terminal of battery; while the circuit for energizing the upper winding of the cut-in relay R99 extends from the positive terminal of battery byway of the contacts 5B, 82 and H5 and the upper winding of R99 to the negativeterminal of battery. When thus energized, the cut-in relay R99 operates to complete, at the contacts 94, an obvious multiple holding circuit for energizing the upper winding thereof and the lower winding of the lockout relay R89. Also, the cut-in relay R99 completes, at the contacts 95, an obvious path for applying positive battery potential to the control conductor CI9I, completes, at the contacts 9|, an obvious path for short-circuiting the resistor 43, and interrupts, at the contacts 92, an obvious path for short-circuiting the winding of the linerelay R59. Accordingly, at this time, the line relay R99 is included in the telegraph line, whereby the winding of the line relay R69 is steadily energized, in the event the telegraph line is idle, and is intermittently energized in accordance with either a message or a code being sent over the telegraph line, in the event the telegraph line is busy.

Also, the cut-in relay R99 completes, at the contacts 93, a circuit for energizing the winding of the step relay R! 39, this circuit extending from the positive terminal of battery by way of the contacts 93 and E59 and the winding of RI30 to the negative terminal of battery. When thus energized, the step relay Rl39 operates to complete, at the contacts ii, a circuit for energizing the motor magnet MI55, this circuit extending from the positive terminal of battery by way of the contacts 93 and I3! and the motor magnet MI to the negative terminal of battery. When thus energized, the motor magnet M555 operates to condition the wipers noted of the sending switch I50 to be driven one step in the counterclockwise direction, and to interrupt, at the contacts I56, the previously traced circuit for energizing the winding of the step relay RI30, thereby to cause the latter relay to restore. Upon restoring, the step relay RI3EI interrupts, at the contacts I3I, the previously traced circuit for energizing the motor magnet MI55, thereby to cause the motor magnet MI55 to restore and drive the wipers noted of the sending switch I50 one step in the counterclockwise direction, and to recomplete, at the contacts I56, the previously traced circuit forenergizing the winding of the step relay RI30; Accordingly, the stepv relay RI39 and the motor magnet MI55 interactin the manner described above, thereby to cause the wipers noted of the sending switch I50 to be 1driven step by step in the'counterclockwise direcion.

When the wiper I53 of the sending switch I50 engages the sixth contact in the associated contact bank, a circuit is completed for energizing the lower winding of the test relay RI 0!], this circuit extending from the positive terminal of battery by way of the contacts 95, CIGI, the wiper I53 of the sending switch I59 and engaged sixth contact in the associated contact bank, CI65, the lower winding of RIEU and the contacts II8 to the negative terminal of-battery. When thus energized, the test relay RIO!) operates to prepare, at the contacts H34, a holding circuit traced hereinafter for energizing the lower winding thereof. At this point, it is noted that, in the event the telegraph line is idle, the winding of the line relay R59 is steadily energized, thereby to cause the line relay R to remain in its operated position; whereupon the previously menticned holding circuit for energizing the lower winding of the test'relayRIEIII is steadily completed at the contacts 5|, this circuit extending from the positive terminal of battery by way of the contacts GI and I94, the lower winding of RIfiIl and the contacts H5 to the negative terminal of battery. On the other hand, in the event the telegraph line is busy, the winding of the line relay R59 is intermittently energized, thereby to cause the line relay R69 to operate intermittently; whereupon the previously traced holding circuit for energizing the lower winding of the test relay RIiit is intermittently completed at the contacts 6|.

Assuming that the telegraph line is idle at this time, the previously traced holding circuit for energizing the lower winding of the test relay RIOD is steadily completed. Accordingly, the test relay Rlilll remains in its operated position when the wiper I53 of the sending switch I59 disengages the sixth contact in the associated contact bank. After the wipers noted of the sending switch I59 have been driven almost one complete revolution, the wiper I53 thereof engages the second contact in the associated contact bank, whereupon a circuit is completed for energizing the winding of the hold relay RI I9, this circuit extending from positive battery potential appearing upon the control conductor CIBI by way of the wiper I53 of the sending switch I59 and engaged second contact in the associated contact bank, CI93, the contacts I92 and the winding of Bi I9 to the negative terminal of battery. When thus energized, the hold relay RI I0 operates to complete, at the contacts H4, a multiple holding circuit for energizing the winding thereof, this circuit extending from the positive terminal of battery by way of the contacts 56 and 82 to the contacts H4 and from the positive terminal of battery by way of the contacts 94 to the contacts H4 and from the contacts II4 by way of the winding of RI I to the negative terminal of battery. Also, the hold relay RI I0 interrupts, at the contacts H8, the previously traced holding circuit for energizing the lower winding of the test relay RI 00, thereby to cause the latter relay to restore. Further, the hold relay RI I0 interrupts, at the contacts I I5, the previously traced original circuit for energizing the upper winding of the cut-in relay R90, whereby an alternative holding circuit is completed for energizing the upper winding of the out-in relay R90, this circuit extending from the positive terminal of battery by way of the contacts 95, CIBI, the resistor I22 and the upper winding of R90 to the negative terminal of battery. Finally, the hold relay RI I0 completes, at the contacts II I, a circuit for energizing the upper winding of the send relay RI20, this circuit extending from the positive terminal of battery by way of the contacts 95, CIGI, the upper winding of RI20 and the contacts II I to the negative terminal of battery.

When thus energized, the send relay RI20 operates, thereby to interrupt, at the contacts I2 I, the telegraph line.

During the second revolution of the wipers noted of the sending switch I50, the wipers I53 and I54 thereof engage the contacts in the lower portions of the associated contact banks, thereby to cause positive battery potential appearing upon the control conductor CIBI to be applied intermittently to the control conductors CIGB and CIB'I. The control conductor CI66 is connected by way of the contacts 84 to the control conductor CI60; while the control conductor CI'I is disconnected at the contacts I4 from the control conductor CI60. Accordingly, at this time, positive battery potential is applied by the wiper I53 of the sending switch I50 to the control conductor CIBB and, consequently, the control conductor CI60, in accordance with the code S, thereby alternately to complete and to interrupt a circuit for energizing the lower winding of the send relay RI20, this circuit extending, when completed, from positive battery potential appearing upon the control conductor CI60 by way of the lower winding of RI and the contacts III to the negative terminal of battery. Hence, the lower winding of the send relay RI20 is energized in accordance with the code S as the wiper I53 of the sending switch I engages the contacts in the lower portion of the associated contact bank. Accordingly, the send relay RI20 operates and restores in accordance with the code S as this relay is of the differential type, thereby to cause the code S to be sent by way of the contacts I2I over the telegraph line. Shortly after the wiper I53 of the sending switch I50 disengages the contacts in the lower portion of the associated contact bank, the wiper I5I thereof engages the contacts in the upper portion of the associated contact bank; and then the wiper I52 thereof engages the contacts in the lower portion of the associated contact bank, whereby additional circuits for energizing the lower winding of the send relay RI20 are successively completed. One of these circuits eX- tends from positive battery potential appearing upon the control conductor CIBI by way of the wiper I5I of the sending switch I50 and the engaged contact in the upper portion of the associated contact bank, CI60, the lower winding of RI20 and the contacts III to the negative terminal of battery; and the other of these circuits extends from positive battery potential appearing upon the control conductor CIBI by way of the wiper I52 of the sending switch I50 and the engaged contact in the lower portion of the associated contact bank, CIBO, the lower winding of RI20 and the contacts III to the negative terminal of battery. Accordingly, the lower winding of the send relay RI20 is then energized in accordance with the codes A and B, thereby to cause this relay to operate and restore in accordance with these codes, whereby the codes A and B are transmitted over the telegraph line.

In view of the above description of the mode of operation of the sending switch I50, it will be understood that, during the second revolution of the wipers thereof, the send relay RI20 is operated to transmit the codes S, A and B over the telegraph line, thereby to cause these codes to be registered by the telegraph recorders 22 and 26 respectively disposed in the telegraph stations TS20 and TS25. The codes S, A and B registered at the telegraph stations TS20 and TS25 indicate to the dispatchers thereat that a train traversing the stretch of railway track I0 and traveling from north to south is at the way station WS30, the identification of the way station WS30 being A and B, as previously noted.

When the wiper I53 of the sending switch I50 has been driven almost two revolutions it reengages the first contact in the associated contact bank, thereby to complete a circuit for energizing the rotary magnet MI43, this circuit extending from positive battery potential appearing upon the control conductor CISI by way of the wiper I53 of the sending switch I50 and the engaged first contact in the associated contact bank, CI62, the contacts I I3 and the rotary magnet MI43 to the negative terminal of battery. When thus energized, the rotary magnet MI43 operates to drive the wipers noted of the counting switch I40 one step in the counterclockwise direction. Subsequently, when the wiper I53 of the sending switch I50 disengages the first contact in the associated contact bank, the previously traced circuit for energizing the rotary magnet MI 43 is interrupted, thereby to cause the rotary magnet MI43 to restore.

In view of the above description of the mode of operation of the sending switch I50, it will be understood that the wipers noted thereof are driven a number of revolutions, thereby to cause the codes S, A and B to be repeated by the send relay RI20 a number of times over the telegraph line, and to cause the rotary magnet MI 43 to be energized repeatedly, whereupon the wipers noted of the counting switch I40 are driven a number of steps. Accordingly, the counting switch I40 counts the number of times that the sending switch I50 causes the send relay RIZI) to send the codes S, A and B over the telegraph line.

When the codes S, A and B have been sent over the telegraph line four times and the wipers noted of the sending switch I50 have been driven almost five complete revolutions, the wiper I53 thereof reengages the first contact in the associated contact bank, thereby to recon plete the previously traced circuit for energizing the rotary magnet MI43, for the fourth time, in order to cause the rotary magnet MI43 to reoperate, for the fourth time, and drive the wipers noted of the counting switch I40 into engagement with the fourth contacts in the associated contact banks. Shortly thereafter, the wipers noted of the sending switch I50 are driven into their normal positions; whereupon the wiper I53 thereof engages the fourth contact in the associated contact bank, thereby to complete a circuit for energizing the lower winding of the cutin relay R90. This circuit extends from positive battery potential appearing upon the control conductor CIiiI by way of the wiper I53 of the sending switch I55 and the engaged fourth contact in the associatedcontact bank, CI54, the wiper MI of the counting switch I and the engaged fourth contact in the associated contact bank, the wiper I 42 of the counting switch I45 and the engaged fourth contact in the associated contact bank, CI58, the contacts H5 and the lower winding of R90 to the negative terminal of battery. When the lower winding of the cutin relay R90 is thus energized, this relay restores as it is of the differential type, as previously noted.

Upon restoring, the cut-in relay R95 interrupts, at the contacts 95, both the previously traced alternative circuit for energizing the upper winding thereof and the above-traced circuit for en-' ergizing the lower winding thereof; and interrupts, at the contacts 93, the previously traced circuit for energizing the winding of the step relay RI35, thereby to cause the latter relay to restore and arrest further operation'of the send-- in-g switch I55. Also, the. cut-in relay R95 interrupts, at the contacts 55, the previously traced circuits for energizing the upper and lower windings of the send relay RIZG, thereby to cause the railway track II], the track circuit for energizing the winding ofthe track relay R55 is recompleted, thereby tocause reoperation of the track relay R55; whereupon the lockout relay R85 and the hold relay RI I0 restore, in the manner previously explained.

Assuming. now that the telegraph line is busy whenithe train traversing thestretch of railway v track It} entersthe track section IOB, at this time the track relays R and Rare restored, theilockout relay R80 and the cut-in relay R90 are operated, and the line relay R operates and restores intermittently, in accordance with the message or code being sent over the telegraph line, in the manner previously explained.

In this event, during the first revolution of the wipers of the sending switch I50, when the wiper I53 thereof engages the sixth contact in the associated contactbank, the previously traced circuit: for energizing the lower'winding of the test relay, RIO!) is completed, thereby to cause the test relay RIF!!! to operate, in the manner previously explained. However, during the first latter relay to restore. Further, the cut-in relay 1 R90 interrupts, at the contacts 9I, the previously mentioned path for short-circuiting the resistor 43, and completes, at the contacts 92, the previously mentioned path for short-circuiting the winding of the line relay R55, thereby to cause the latter relay to restore.

The release of the remainder of the apparatus, at the Way station W830 depends upon whether the track section IiiB of the stretch of railway track I5 is clear or is still occupied by the train. Assuming that I the track section stretch of railway track I5 is clear at this time, thetrack circuits of the track sections IGA and ItlB of the stretch of railway track I0 have been recompleted, thereby to cause reoperation of the track relays R55 and R55. Upon reoperating, the track relay R55 interrupts, at the contacts M, the previously traced circuit for energizing the upper winding of the lockout relay R88; and, upon reoperating, the track relay R55 interrupts, at the contacts 55, the previously traced holding circuit for energizing the lower winding of the lockout relay R55, thereby to cause the latter relay to restore. liurther, the track relay R55 interrupts, at the contacts 56, the previously traced alternative holding circuit for energizing the winding of the hold relay RI Iii, thereby to cause the latter relay to restore shortly thereafter, the hold relay RI it! being of the slow-to-release type. At this time, the apparatus at the way station W835 is completely released.

On the other hand, in the event the train has not cleared the track section IHB of the stretch of railway track it, when the cut-in relay R90 restores, after the codes S, A and B have been transmitted four times over the telegraph line as previously explained, the previously traced alternative holding circuit for energizing the winding of the hold relay RI I5 is completed at the contacts 55, due to the restored condition of the track relay R55. Also, the restored track relay R55 retains completed, at the contacts 55,

IGB of the.

revolution ofthe wipers of the sending switch I50, whenthe wiper I53 thereof disengages the sixth contact in the associated contact bank, the previously traced circuit for energizing'the lower winding of the testrelay RIM is interrupted;

; and the previouslytracedholding circuit for energizing the lower winding of the test relay RIOt'is completed intermittently'at the contacts 5|,- due to the intermittent operation of the line relay-11250.; Accordingly, the test relay RIM! restores during'the first revolution of the wipers noted of the sending switch I50. Hence, when the, wipers noted of the sending switch I50 are driven almost one complete revolution the wiper I53, thereof engages thesecond contact in the associated contact bank while the test relay RIM occupies its restored position. When the wiper I53 ofthe sending switch I50 engages the second-tcontactin the associated contact bank, an

alternative circuit for energizing the rotary magnet MI43 is completed, this circuit extending from positive battery potential appearing upon thecontrol conductorCIBI byway of the wiper I53 of ,thesending switch I50 and the engaged second contact in the associated contact bank,

(H53, the contacts IllI and H2 and the rotary magnet MI43 to, the negative terminal of battery. .When thus energized therotary magnet MI43 operates,thereby to drive the wipers noted of the counting switch I40 one step, in the manner previously, explained.

' .After the wipers noted of the sending switch test relay RI IN] again recompletes, at the contacts I54, the previously traced holding circuit for energizing the lower winding thereof, which holding circuit is again intermittently completed in the event the telegraph line is busy, due to the intermittent operation of the line relay R60.

In view of the above explanation of the mode of operation of the apparatus at the way station WS30, while the telegraph line is busy, it will be understood that, upon each revolution of the wipers noted of the sending switch 150, the wiper I53 thereof first engages the second contact in the associated contact bank and then the sixth contact in the associated contact bank, thereby to recomplete first the previously traced alternative circuit for energizing the rotary magnet M143 and then the previously traced circuit for energizing the lower winding of the test relay R100; whereby the wipers noted'of the counting switch 140 are driven step by step and the test relay R100 is operated and restored repeatedly. Accordingly, the test relay R100 re-' peatedly tests the telegraph line in order to determine the idle or busy condition thereof; while the counting switch 140 counts the number of times the telegraph line is tested as busy as the wipers noted of the sending switch 150 are driven through a number of revolutions.

It is noted that the operation of the sending switch 150 causes the test relay R100 to test the idle or busy condition of the telegraph line five times successively at spaced time intervals; and that, in the event the telegraph line becomes idle at any time during these five tests, the test relay R100 remains in its operated position, due to the previously traced completed holding circuit for energizing the lower winding thereof,

the line relay R60 remaining steadily operated in the event the telegraph line is tested as idle. In this event, when the wipers noted of the sending switch 150 are driven almost any complete revolution, less than almost five complete revolutions, the wiper 153 thereof engages the second contact in the associated contact bank, While the test relay R100 occupies its operated position, thereby to complete the previously traced circuit for energizing the winding of the hold relay R110. When thus energized, the hold relay R110 operates, at this time, to complete, at the contacts I 11, a holding circuit for energizing in series the upper winding of the test relay R100 and the release magnet M144. This circuit extends from the positive terminal of battery by way of the contacts 103, the upper winding of R100, the contacts 111, the set of switch springs SS145 and the release magnet M144 to battery. When thus energized, the release magnet M144 operates, thereby to release the wipers noted of the counting switch 140 and to cause them to be returned to their normal positions; whereupon the set of switch springs SS145 is actuated into disengagement, thereby to interrupt the previously traced circuit for energizing in series the upper winding of the test relay R100 and the release magnet M144. The release magnet M144 then restores. Also, the test relay R100 restores as the previously traced holding circuit for enegizing the lower winding thereof is interrupted at the contacts 118, incident to operation of the hold relay R110; and the previously traced circuit for energizing the upper winding thereof is interrupted when the set of switch springs SS145 is actuated into disengagement.

Also, upon operating, the hold relay R110 recompletes, at the contacts 114, the previously traced multiple holding circuit for energizing the winding thereof, and completes, at the contacts 111, the previously traced circuit for energizing the upper winding of the send relay R120, thereby to cause the latter relay to operate.

The subsequent operation of the apparatus at the way station W838, in order to cause the codes S, A and B to be sent four times by the send relay Rlrlil over the telegraph line, is the same as that previously explained; also, the release of the apparatus at the way station WS30, after the codes S, A and B have been sent four times by the send relay R over the telegraph line, is the same as that previously explained. 10.

Assuming now that the telegraph line remains busy during the repeated tests thereof by the test relay R100, when the wipers noted of the sending switch 150 are driven almost five revolutions the wiper thereof engages the second contact in the associated contact bank, thereby to recomplete, for the fifth time, the previously traced circuit for energizing the rotary magnet M143. The rotary magnet Nil-i8 then operates, for the fifth time, thereby to drive the wipers noted of the counting switch Mil into engagement with the fifth contacts in the associated contact banks. When the wipers-noted of the counting switch are driven into engagement with the fifth contacts in the associated contact banks, an alternative circuit for energizing the lower winding of the test relay R5 00 is completed, this circuit extending from the positive terminal of battery by way of the control conductor C169, the wiper 142 of the counting switch 140 and the engaged fifth contact in the associated contact bank, the wiper 141 of the counting switch 140 and the engaged fifth contact in the associated contact bank, the control conductor C165, the lower winding of R100 and the contacts 118 to the negative terminal of battery. When thus energized, the test relay Rim) operates and remains operated, regardless of the intermittent operation of the line relay R50 during the sixth revolution of the wipers noted of the sending switch 150.

When the Wipers noted of the sending switch 150 are driven almost six revolutions, the wiper 153 thereof engages the second contact in the associated cont-act bank, thereby to complete the previously traced circuit for energizing the winding of the hold relay R110. When thus energized, the hold relay R113 operates, thereby to complete, at the contacts 114, the previously traced multiple holding circuit for energizing the winding thereof; to complete, at the contacts 111, the previously traced series circuit for energizing the upper Winding of the test relay R100 and the release magnet M544; to interrupt, at the contacts 118, the previously traced alternative circuit for energizing the lower winding of the test relay Rim); and to complete, at the contacts 111, the previously traced circuit for energizing the lower winding of the send relay R120. The release magnet Midd operates, thereby to cause the release of the wipers noted of the counting switch 141), in the manner previously explained; whereupon the set of switch springs SS is actuated, thereby to interrupt the previously traced series circuit for energizing the release magnet M144 and the upper winding of the test relay R100, whereupon the release magnet M144 and the test relay R! $30 restore.

Accordingly, the apparatus at the way station W830 seizes the busy telegraph line in the event it is successively tested five times as busy by the test relay R100. The subsequent operation of the sending switch 555 to cause the send relay R120 to send the codes S, A and B over the telegraph line, even though the telegraph line is busy, is the same as that previously explained; also, the release of the apparatus at the way station W830, after the codes 8, A and B have been sent four times by the send relay R|20 over the telegraph line, is the sameas that previously explained.

When a train traversing the stretch of railway track l from south to north enters the track section 103, the winding of the track relay R55 is short-circuited, thereby to cause the latter relay to restore. Upon restoring, the track relay R55 completes, at the contacts 50-, the previously mentioned circuit for energizing the upper winding of the lookout relay R10, this circuit extending from the positive terminal of battery'by way of the contacts 50 and 83 and the upper winding of R10 to the negative terminal of battery. When thus energized, the lockout relay R10 operates to interrupt, at the contacts H, a point in the previously traced circuit for energizing the upper winding of the lookout relay R80; and to. prepare, at the contacts 14, a' circuit substantially identical to that previously traced for energizing the lower winding of the send relay Ri20 and including the lower portion or the contact bank associated with the wiper I54 of the sending switch I50. 7

When the train traversing the stretch of railway track I0 enters the track section [0A, the winding of the track relay R50 is short-circuited, thereby to cause the latter relay to restore. Upon restoring, the track relay R50 completes, at the contacts 51, a holding circuit for energizing the lower winding of the'lockout relay R10 and a circuit for energizing the upper winding of the cut-in relay R90. The holding circuit for energizing the lower winding of the lookout relay R70 extends from the positive terminal of battery by way of the contacts '52 and13 and the lower winding of R to the negative terminal of battery; while the circuit for energizing the upper winding of the cut-in relay R00 extends from the positive terminal of battery by way of the contacts 5|, l2 and 'I I5 and the upper winding of R9 1 to the negative terminal of battery. When thus energized, the cut-in relay R90 operates to complete, at the contacts 94, an obvious multiple holding circuit for energizing the upper winding thereof and the lower winding of the lookout relay Rid. Also, the cut-in relay R90 completes, at the contacts 85, the previously mentioned path for applying positive battery potential to the control conductor Clfil; completes, at the contacts 9!, the previously mentioned path for short-circuiting the resistor 43; and interrupts, at the contacts 92, the previously mentioned path for short-circuiting the winding of the line relay R50. Also, the cut-in relay R90 completes, at

the contacts 93, the previously traced circuit for energizing the winding of the step relay RI30, thereby to initiate interaction of the step relay RI30' and the motor magnet Ml55, whereby the wipers noted of the sending switch I50 are driven step by step in the counterclockwise direction, in the manner previously explained.

The subsequent operation of the apparatus, in order to test the idle or busy condition of the telegraph line, to send four times the selected code in the event the telegraph line is tested idle, to test five times the telegraph line in the event it is tested busy, and to send four times the selected code after the telegraph line has been tested five times asbusy, are substantially the same, as previously described. Further, the release of the apparatus at the way station W830, after the train traversing thestretch of railway patchers thereat that a train traversing the stretch of railway track from south to north has entered the track section 10A adjacent the way station W830.

In connection with the apparatus at the way station W830, it is pointed out that the test relay RI00, the counting switch I40 andthe sending switch I50 are so related that the telegraph line is tested as busy five times before it is seized and the codes are sent thereover when it is busy; while the counting switch I40 and the sending switch I 50 are so related that codes are sent over the telegraph line four times after it is seized. This arrangement permits the apparatus at two spaced-apart way stations to be initiated sub stantially simultaneously without interference,

due to the fact that the apparatus at one of the way stations will seize the telegraph line and send the associated codes thereover fourtimes before the other of the way stations has tested the telegraph line as busy five times. Accordingly, this arrangementprevents interference between the apparatus at two spaced-apart way stationswhen operations'of the apparatus thereat are initiated substantially simultaneously. Also, this arrangement permits the dispatcher at one of the stations to finish a short-message which is being transmitted over the telegraph line before the apparatus at one of the way stations seizes the telegraphline to send the corresponding codesthereover.

From the foregoing description of the traffic signaling system, it will be apparent that'an improved arrangement is provided for controlling the transmission of codes from a plurality of way stations associated with a common telegraph line in a noninterfering mariner.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such 'modifications as fall within the true spirit and scope of the invention.

What is claimed is:

' 1. In a signaling system including a signal line which is rendered busy only while a signal is being sent thereover; means for testing repeatedly at spaced time intervals the idle or busy condition of said signal line, a sender operative to send a signal over said signal line,'means controlled in' response to the testing of said signal line as idle for operating said sender, and additional means controlled in response to .the testing of said signal line as busy a predetermined number of times'for operating said sender regardless of the busy condition of said signal line. 2. In a signaling system including a signal line which is rendered busy only while a signal is being sent thereover; means for testing repeatedly at spaced time intervals the idle or busy condition of saidsignal line, a sender operative to send a signal over said signal line, means controlled in response to the testing of said signal line as idle for operating said sender, counting mechanism,

means for operating said counting mechanism each time said signal line is tested as busy, and additional means controlled in response to the operation of said counting mechanism a predetermined number of times for operating said sender regardless of the busy condition of said signal line.

3. In a signaling system including a signal line which is rendered busy while a signal is being sent thereover; means for testing repeatedly at spaced time intervals the idle or busy condition of said signal line, a sender operative repeatedly to send at spaced time intervals a signal over said signal line, means controlled in response to the testing of said signal line as idle for initiating operation of said sender, counting mechanism, means for operating said counting mechanism each time said signal line is tested as busy, additional means controlled in response to the operation of said counting mechanism a predetermined number of times for initiating operation of said sender regardless of the busy condition of said signal line, means controlled when operation of said sender is initiated for releasing said counting mechanism in the event it is operated, additional means for operating said counting mechanism each time said sender operates to send said signal over said signal line, and means controlled in response to the last-mentioned operation of said counting mechanism a given number of times for arresting operation of said sender.

4. In a signaling system including a signal line which is rendered busy only while a signal is being sent thereover; a device operative repeatedly through a cycle at spaced time intervals, means for initiating operation of said device, means responsive to each of a predetermined number of cycles of operation of said device for testing the idle or busy condition of said signal line, means controlled after said signal line is tested as idle for sending a predetermined signal thereover upon each subsequent cycle of operation of said device, additional means controlled after said signal line is tested as busy said predetermined number of times for sending said predetermined signal thereover upon each subsequent cycle of operation of said device regardless of the busy condition of said signal line, and means controlled in response to the sending of said predetermined signal over said signal line a given number of times for arresting operation of said device.

5. In a signaling system including a signal line which is rendered busy while a signal is being sent thereover; a sending switch operative repeatedly through a cycle at spaced time intervals, means for initiating operation of said sending switch, means responsive to each of a predetermined number of cycles of operation of said sending switch for testing the idle or busy condition of said signal line, means controlled in response to the testing of said signal line as idle for operatively connecting said sending switch to said signal line, whereby a predetermined signal is sent over said signal line upon each subsequent cycle of operation of said sending switch, a counting switch, means for operating said counting switch each time said signal line is tested as busy, additional means controlled in response to the operation of said counting switch said predetermined number of times for operatively connecting said sending switch to said signal line regardless of the busy condition thereof, whereby said predetermined signal is sent over said signal line upon each subsequent cycle of operation of said sending switch, means controlled when said sending switch is operatively connected to said signal line for releasing said counting switch in the event it is operated, additional means for operating said counting switch each time said predetermined signal is sent over said signal line, and means controlled in response to the last-mentioned operation of counting switch a given number of times for arresting operation of said sending switch.

6. In a signaling system including a signal line which is rendered busy while a signal is being sent thereover; a line relay, means for holding operated said line relay when said signal line is idle and for operating intermittently said line relay when said signal line is busy, 2. device operative repeatedly through a cycle at spaced time intervals, means for initiating operation of said device, a test relay, means controlled when said line relay is held operated and upon any of a predetermined number of cycles of operation of said device for holding operated said test relay, means controlled when said line relay is operating intermittently and upon each of said predetermined number of cycles of operation of said device for causing operation and subsequent restoration of said test relay, additional means controlled upon said predetermined number of operations and subsequent restorations of said test relay for holding operated said test relay, a sender operative to send a signal over said signal line, means controlled when said test relay is held operated for operating said sender, and

means controlled after said signal has been sent 7 over said signal line for arresting operation of said device.

7. In a signaling system including a signal line which is rendered busy while a signal is being sent thereover; a sending switch operative repeatedly through a cycle at spaced time intervals, means for initiating operation of said sending switch, means controlled by said sending switch for testing the idle or busy condition of said signal line upon each of a predetermined number of cycles of operation of said sending switch, means controlled jointly in response to the testing of said signal line as idle and by said sending switch for operatively connecting said sending switch to said signal line, whereby said sending switch sends a predetermined signal over said signal line upon each subsequent cycle of operation thereof, additional means controlled jointly in response to the testing of said signal line as busy said predetermined number of times and by said sending switch for operatively connecting said sending switch to said signal line, whereby said sending switch sends said predetermined signal over said signal line upon each subsequent cycle of operation thereof regardless of the busy condition of said signal line, and means controlled jointly in response to the sending of said predetermined signal over said signal line a given number of times and by said sending switch for arresting operation of said sending switch.

8. In a signaling system including a signal line which is rendered busy while a signal is being sent thereover; a tester operative repeatedly to test the idle or busy condition of said signal line, a sender operative repeatedly to send a predetermined signal over said signal line, means for initiating operation of said tester, means responsive to the testing of said signal line as idle for arresting operation of said tester and for initiating operation of said sender, counting mechanism, means for operating said counting mechanism each time said signal line is tested as busy, additional means responsive to the operation of said counting mechanism a predetermined number of times for arresting operation of said tester and for initiating operationof said sender, means controlled when operation of said sender is initiated for releasing said counting mechanism in the event it is operated, additional means for operating said counting mechanism each time said predetermined signal is sent over said signal line, and means responsive to the last-mentioned operation of said counting mechanism a given number of times for arresting operation of said sender.

9. In a signaling system including a signal line which is rendered busy While a signal is being sent thereover and a plurality of signal stations associated with said signal line; each of said signal stations comprising means for testing repeatedly at spaced time intervals the idle or busy condition of said signal line, a sender opvresponse to the operation of said counting mechanism a predetermined number of times for initiating operation of said sender regardless of the busy condition of said signal line, means controlled when operation of said sender is initiated for releasing said counting mechanism in the event it is operated, additional means for operating said counting mechanism each time said sender operates to send said signal over said signal line,-and means controlled in response to the last-mentioned operation of said counting mechanism a given number of times for arresting operation of said sender, said predetermined number being greater than said given number.

KURT MULLERHEIM. 

